The human spine has a normal, healthy structure with certain curves that provides for proper balance and shock absorption. However, aging, disease and injury can affect the spinal structure causing debilitating pain and immobilization. For instance, Scoliosis is a disease that imparts an unhealthy curvature to the spine.
In describing the shape and structure of the spine, it is important to discuss a few anatomical terms. The transverse axis (also the X-Axis) extends from left to right. The longitudinal axis (also the Y-Axis) extends from the head to the feet. The sagittal axis (also the Z-Axis) extends anterior to posterior. A lateral traction force is exerted in the transverse (left-to-right) axis. A distraction force is exerted in the longitudinal (head-to-foot) axis. A sagittal force is exerted in the sagittal (front-to-back) axis.
The natural, healthy spinal structure includes curves in the sagittal plane—the spine curves from front to back to provide proper balance and shock absorption. When viewed from the side, the cervical and lumbar vertebrae form healthy lordotic (concave toward the back of the spine) curves and the thoracic vertebrae form a healthy kyphotic (convex toward the back of the spine) curve. With Scoliosis, the spine curves in an unhealthy manner on the transverse plane—from left to right. This curve compromises the spine's ability to provide balance and support the weight of the head and upper body.
Improper spine structure is generally treated with exercise, physical medicine or surgery. Physical medicine uses traction—the application of a force to the patient's body in one or more of the above-described axes—to adjust the structure of the spine. Physical medicine can also be used to reshape the soft tissues—such as ligaments, tendons, and muscles—that support the spine in its unhealthy structure.